The month Chislev (v. 1) corresponds to our late November and early December. The year in view was the twentieth year of Artaxerxes' reign (i.e., 445-444 B.C.). Susa (or Shushan, in Hebrew) was a winter capital of Artaxerxes (cf. Esth. 1:2). The main Persian capital at this time was Persepolis.
Hanani (v. 2) seems to have been Nehemiah's blood brother (cf. 7:2). The escape in view refers to the Jews' escape back from captivity in Babylon. Even though they received official permission to return, Nehemiah seems to have regarded their departure from Babylon as an escape since the Babylonians had originally forced them into exile against their wills.
The news that Nehemiah received evidently informed him of the Jews' unsuccessful attempts to rebuild Jerusalem's walls in 458 B.C. (Ezra 4:23).
"It was an ominous development, for the ring of hostile neighbors round Jerusalem could now claim royal backing. The patronage which Ezra had enjoyed (cf. Ezra 7:21-26) was suddenly in ruins, as completely as the city walls and gates. Jerusalem was not only disarmed but on its own."6
